What is the best way to adjust the Color Temperature Gain and Offset controls of my DLA-RS57?

The Gain and Offset adjustments are calibration controls used by professionals and enthusiasts to balance the color temperature of the bright and dark video levels. Do not adjust these controls unless you know how to calibrate a projector and have a professional color meter. We recommend that calibrators use 20% gray level for Offsets and 80% gray level for Gains.